1. Field of the Invention
The present invention relates to a wrench, and more particularly to a wrench for an engine clutch of a radio control model.
2. Description of Related Art
The power from the engine of a radio control model is transmitted to the drive device via a clutch. With reference to FIG. 10, the clutch includes a seat (1) having an input shaft (2) centrally longitudinally mounted to the seat (1) and connected to the engine of the radio control model. Three stubs (3) extend from the seat (1) opposite to the engine and respectively radially correspond to the input shaft (2). One of the three stub (3) has a centrifugal lever (4) pivotally sleeved thereon. The centrifugal lever (4) includes a through hole (4A) longitudinally defined in one side of the centrifugal lever (4) and a slot (4B) laterally defined to perpendicularly communicate with the through hole (4A). The through hole (4A) is sleeved on a corresponding one of the three stubs (3) after a torsion spring (5) being disposed in the slot (4B) and the corresponding stub (3) extending through the torsion spring (5) for positioning the torsion spring (5). The torsion spring (5) has a first end (5A) and a second end (5B) respectively engaged to the input shaft (2) and the centrifugal lever (4).
The centrifugal lever (4) is outwardly wiggled due to the centrifugal force due to the rotating seat (1) that is drive by the input shaft (2). The wiggled centrifugal lever (4) is engaged to an inner periphery of a coupling (not shown) for driving the coupling due to the friction force between the wiggled lever (4) and the coupling. The centrifugal lever (4) is disengaged from the coupling when the seat (1) is stopped.
The centrifugal lever (4) is easily worn out because the radio control model is usually operated in a high speed. Consequently, the user frequently needs to exchange the worn centrifugal lever (4). However, the centrifugal lever (4) of the clutch of the radio control model is a very small part such that the user difficultly uses the ordinary hand tool, such as pliers and screwdriver, to exchange the worn centrifugal lever. A unique tool is necessary to conveniently exchange the centrifugal lever (4) of the engine clutch of a radio control model.
The present invention has arisen to mitigate and/or obviate the disadvantages of the conventional hand tools that are difficultly used to exchange the worn centrifugal lever.